We know that Demon Slayer: Kimetsu no Yaiba is huge right now, so if you want some free manga merch, you might want to start collecting stamps ASAP to get your hands on that sweet, sweet Demon Slayer merchandise. If that doesn't appeal to you, Lawson is selling tie-up snacks (like onigiri and pastries) in Demon Slayer packaging too, which deliver a little more instant gratification.